The collapsible steering column has an upper steering shaft, an intermediate steering shaft connected to the upper steering shaft by a universal joint and a jacket housing that moves forward during steering column collapse and envelopes the universal joint.
Vehicle steering columns that collapse during a collision are employed on many land vehicles manufactured today. These collapsible steering columns have an energy absorption device that limits the rate of collapse and reduces the maximum force applied to a vehicle driver during the collapse.
The force applied to the vehicle driver is limited by stopping the driver and the steering wheel at a slower rate than the vehicle passenger compartment is stopped. The distance the driver can travel relative to the vehicle passenger compartment during a collision is limited by the windshield, the instrument panel and other vehicle components.
Steering columns, that are currently manufactured, have an upper steering column shaft mounted in a steering column jacket assembly that collapses a distance substantially equal to the total steering column collapse distance. This results in a steering column jacket assembly that is relatively long. A long steering column jacket assembly reduces the space between the driver and the vehicle firewall that is available for other vehicle components. It is frequently necessary to move some vehicle components forward into the engine compartment to accommodate the length of the steering column jacket assembly. Engine compartments of many current vehicles are too crowded with vehicle components making vehicle maintenance difficult and expensive. Engine compartments are hot and dirty. The dirt includes abrasive materials and undesirable gasses. This combination increases maintenance requirements and reduces the life of some vehicle components.
The lack of available space in some vehicles may make it necessary to reduce the available travel distance between the steering wheel and the vehicle body to accommodate the steering jacket assembly. Reducing the distance the steering wheel can move relative to the passenger compartment during a collision reduces the protection available.
Vehicle designers strive to provide the maximum protection for vehicle occupants. They are constrained by manufacturing costs, vehicle operating costs and functional considerations.
The collapsible vehicle steering column includes a steering column jacket housing. An upper shaft assembly having a variable length is journaled in the steering column jacket housing. An intermediate steering shaft with a universal joint connects the intermediate steering shaft to the upper shaft assembly. Both the intermediate steering shaft and the upper shaft assembly control forward movement of the steering column jacket housing during a collision.